[Xen-devel] [PATCH 8 of 9] x86/mm: Make sharing ASSERT check more accurate

[Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>]

 xen/arch/x86/mm/mem_sharing.c |  7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)


Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>

diff -r 244804e8a002 -r 12f7da67cefe xen/arch/x86/mm/mem_sharing.c
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -197,7 +197,12 @@ static struct page_info* mem_sharing_loo
         struct page_info* page = mfn_to_page(_mfn(mfn));
         if ( page_get_owner(page) == dom_cow )
         {
-            ASSERT(page->u.inuse.type_info & PGT_type_mask); 
+            /* Count has to be at least two, because we're called
+             * with the mfn locked (1) and this is supposed to be 
+             * a shared page (1). */
+            ASSERT( (page->u.inuse.type_info & 
+                     (PGT_shared_page | PGT_count_mask)) >=
+                    (PGT_shared_page | 2) ); 
             ASSERT(get_gpfn_from_mfn(mfn) == SHARED_M2P_ENTRY); 
             return page;
         }

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